Printing telegraph system



Nov. 10, 1953 J; D.'DURKEE PRINTING TELEGRAPH SYSTEM Filed Aug. 11 1949 FREQ. A 55 Q-B 3 firm. 0 7 mm. .0

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transmitter. The radio frequency wave containing the coded audio frequency permutation or combination is received by a radio frequency receiver which demodulates it into its audio frequency components and delivers them to the field coils of a series of tuned reeds or resonant relays as audio frequency impulses. These resonant relays, which are individually resonant with one of the audio frequencies contained in the permutation or combination, begin vibrating at the frequency to which they are resonant. When the vibrations of the individual resonant relays reach full amplitude, an impulse of direct current is applied to a relay or gas triode which stores the impulse, electromagnetically, until a mechanism for translating the code permutation or combination into printed characters is actuated.

While I have referred to the use of tuned reeds in the mechanism of my invention, I desire that it be understood that I may replace the tuned reeds by electrical filters, particularly at the higher frequencies for accomplishing a similar purpose.

Since the vibration of the tuned reeds of the resonant relays are affected primarily by the resonance of the impulses with the natural period of the reeds rather than by the amount of power in each impulse, the action of the reeds is not greatly affected by fading signals and, since impulses which are not resonant with the reeds, regardless of power, will not cause the reeds to vibrate at full amplitude, no direct current is transferred to the latching relay or gas tube, and thus no code permutation or combination is presented to the translating mechanism. Therefore, the system is substantially unaffected by interfering signals or static.

Conversely, if the audio frequency oscillations are continuously applied andthe reeds maintained at full amplitude of vibration and the coded permutation or combination is forme by the discontinuance of combinations of the audio frequency oscillations, the vibration of the affected reeds will drop below the amplitude which maintain continuous flow of current to the relays, thus presenting coded combinations as represented by the reeds remaining in contact.

Practically all modern printing telegraph systems and equipment utiliz the principl of sequential application of some form of coded permutations or combinations. These methods require accurate synchronism between transmitting and receiving points, in addition, the speed of these methods is limited by the requirement for linear translation of code permutations or oombinations in terms of time. Thus, if each coded permutation or combination is spaced second apart,.the limit is five characters per second.

By the simultaneous application of the coded permutations or combinations'as accomplished by my invention, no limitationin time of translation is involved and the speed is limited only by the ability of the translation mechanism to In the presently available printing telegraph systems and equipment, the sequentially spaced In the method of my invention, the coded audio frequency impulses are translated into direct our r'ent impulses which are electrically translated into Printe ar c t s e t s e n u are mechanically translated into printed characall printing operations as well as providing complete flexibility of transference to any position.

Description of transmitting apparatus The operation of the system of my invention as a printing telegraph device may be understood-- by reference to Fig. 1 in which a keyboard is provided consisting of a group of letter, figure and functional depressible pivotally mounted keys 36, each having a key-return spring 31, and an associated set of five selector bars 38 connected to key 36 by wires 39. Reference character represents five sets of electrical contacts which are closed in permutations or combinations when a letter or other functional key 36 is depressed. Reference character 4! designates a multiple audio frequency oscillator-amplifier capable of generating five different audio frequency tones singly or in simultaneous permutations or combinations. Reference character 42 denotes a coupling transformer between the oscillator 4| and a modulator 43 which modulates the radio frequency carrier generated in the oscillator-amplifier equipment 44, which in turn radiates a modulated radio frequency signal through antenna system 45. V

When key 36,15 depressed the wires 39 pull down a combination of bars 38 which in turn close the electrical contacts 40, associated with each bar. When the selected contacts 40 are closed the oscillators 4! associated with eachset of con;- tacts 40 which have been closed are caused to produce oscillations at the audio frequency to which they have been tuned. The output of the actuated oscillator 41 is then combined in coupling transformer 42 which drives modulator 43 causing the radiofrequency output of amplifier 44 to'be modulated at the selected audio frequencies and radiated into space through antenna 45. In addition to the method described, the audio frequency tones may be impressed upon a pair of conductors or upon a carrier frequency which is transmitted by wire lines instead of radiated into space.

In Fig. 2 I have shown the schematic wiring diagram of thetransmitter where the audio frequency oscillators are illustrated at Ma, 4lb, 4Ic, 41d and Me, including resistance capacity coupled oscillator circuits 45a, 451 460, 46d and 46a associated with oscillator amplifiers 41a, 41b, 41c, 41d andfle' respectively. The contacts 40 are shown for each of the respective oscillator systems at'40a, 40b, 40c, 40d and 406 connected to the transformer system 42 through which the selected audio frequencies are impressed upon modulator 43 for keying oscillator system 44 and impressing the selected modulated frequencies on antenna system 45. f

Description of receiving system Fig. 3 is a block diagram of the receiving system of my invention operating as a tape printing telegraph device. Inoperation'thepeceiver' 50 picks up the radio signal emitted by antenna system 65 of Figs. 1 and 2 on antenna. system and demodulates the signalsand passes the rectified impulses through the field coils of tuned reed relays 52A,B, C, D, andE, These impulses cause the selected tuned reed relay armatures 53A, B, C, D, and E to vibrate in resonance with the audio frequency tones selected to produce the desired permutation or combination. When the vibrating relay armatures 53A, 3, C, D, 01' E reach their amplitude of vibration, direct current impulses are presented to'the fieldcoils of relays 54A, 3.

7 other special characters such as weather symbols and the like under supervision of the second arm 94 extending in approximately diametrically opposite position with respect to arm 58 and also rotatable about shaft 6|.

It may be observed that the stepping relay is re-cycling and that the code wheel 84 has two complete alphabets, each occupying one-half the periphery of the wheel. The alphabets are associated with the respective arms 58 and 94. Since the device is re-cycling thereis no need to reset the mechanism after the rinting of each character since one of the rocking arms 58 and 94 steps forward to the next character from'the position of the last printing. After one arm completes 180 travel the other arm picks up the rotation through 180.

The mechanism of my invention is extremely compact in size because of the arrangement of the control system. The dimensional arrangement is such that the type wheel of drum B4 and the associated tape advancing mechanism and the ratchet mechanism for controlling the movement of arms 58 and 94 are all located substantially within the dimensional limits of the approximately 180 angular range of the stepping relay 51. Thus, the printer unit takes on the appearance of the substantially 180 contact system A-Z. which is located closely adjacent the type wheel and the associated operating parts and substantially embraces the dimensional limits thereof.

Tapev advance is accomplished by operating ratchet relay which turns roller H by operating arm H to step ratchet i2 whenever contacts 69 are closed as a result of the release of armature 65 by the removal of energy from relay coil 8| or by the completion of channel 29 or matrix 56 as a result of the receipt of a "space? combination signal over channel 93.

Operation The operation of the system of my invention is as follows: Assume it is desired to print the character Y which is represented by the simultaneous application of the tones produced by oscillators Ma. and Md. 7

, The letter key Y of keyboard of Fig. l is depressed causing contacts 40 associated with oscillators Mb and Md to be closed. The output. ofthese two oscillators causes modulator 43 to modulate amplifier 4.4 at the frequency tones produced by oscillator Mb and did. The amplifier in turn emits these tones on a radio frequency carrier.

. Receiver and amplifier signahdemodulates and passes the rectified impulses as audio frequency tones to the coils of tuned reed relays 52B and 521) which begin vibrating at their resonant frequencies and when 'sufiicient amplitude of vibration is attained, contacts are made at 143 and 74D which in turn causes, field coils 15B and 15D of the relays 54B and 541) to move armatures 55B and 55D which moves extended actuators EBB and MD to one limiting position thereof, closing the marking contacts and opening the spacing contacts of the arms associated with actuators 16B and 16D. With actuators 'IGB'and 55D inthe limiting position above described an electricalp-ath is provided through channel I of matrix 55 from the negative side of the source of battery to relay coil Sl'to contact 6217 of stepping relay 62 on stepping switch 51.

. When actuators 16B and 75D are moved from their original position, the path through matrix 50 pick up this emitted 56' provided by channel 3! was interrupted, causing current to be withdrawn from relay 82 allowing contact 81 to close. The closing of contact 81 supplies current to stepping relay 62 from the positive source of battery through the winding of relay 62 and contacts 62b to the negative source of battery and ground, causing ratchet 59 to start stepping arm 58. When arm 58 arrives at position A, the upward stroke of armature 62a does not break the source of current, since by the closing of electrical circuit through channel I of matrix 56, the coil of relay 8| was placed across contact 62b, keeping coil 62 energized which in turn stopped the movement of armature 62a and ratchet 59. When the movement of arm 58 was arrested the rotation of drum 64 was also stopped at a position where the letter Y was immediately above tape 66 and armature 65 striking surface 65a. The electrical energy which provided the holding current for relay 62 to arrest the movement of arm 58 also passed through relay coil BI causing armature 65 to move upward which pressed tape 66 against the letter Y, causing the letter Y to be printed on tape 66.

As previously described, the return of key Y to normal position on keyboard 35 of Fig. 1 removed the output of oscillators Alb and Mc from modulator 43 and amplifier M, which in turn caused tuned reeds 52B and 52D to discontinue vibration, breaking contacts 14B and MD allowing relays 54B and 5413 to return to normal which moved actuators "MB and MD to their original position. In this position channel 3i was closed which closed relay 8! removing the battery source from relay 8! and stepping relay 57. The removal of energy from relay 8i caused contacts 69 to close providing an electrical circuit from the positive side of the battery source through relay F0 to the negative battery supply which in turn caused relay armature H to operate ratchet 12 moving rollers H and I8 advancing tape 66 one step forward.

While my invention as hereinbefore described has been illustrated as applied to a tape type of printer, the operation may be applied to a page type printer by replacing the stepping relay 58 and associated apparatus with a conventional electric typewriter.

The thirty-two channels of matrix 56 are then used to provide an electrical circuit to a series of thirty two solenoids or relays which are used to operate the mechanism of the electric typewriter which performs the typing, carriage return, line feed, spacing and upper and lower case functions.

In applications where more or less than thirty two operations are required, the number of oscillators, tuned reeds and associated relays may be rearranged in a matrix which will perform the number of functions required.

One such application is in the use of drums to A visually present pre-arranged or recorded information.

Where thenumber of displays to be presented are less than sixteen, four tones, four tuned reeds, a sixteen channel matrix and a sixteen position stepping relay with the messages printed on a cylindricalsurface such as the drum 64 of Figs. 3 and 4, can be formed into a light weight system of visual telegraphy particularly adapted to aviation trafi'ic control communications;

Another application of my invention is an arrangement of the matrix156 where one channel is permanently wired in a fixed position in such a-manner that-only when'a signal consisting of the proper combination of tones is received will it pass through the matrix. Such anapplication being particularly adapted to selective calling systems illustrates the versatile character of the system of my invention.

The matrix 56 illustrated in Fig. :4 shows in diagrammatic form the graphic appearance of the code symbols used in the system of my invention. These are standard codecharacters of the international Teletype code with respect-to the sequential arrangement of the mark and space signal impulses. The equipment of my invention is accordingly interchangeable with standard Teletype equipment and is operative over the'same channels on whichstandard Tele typeequipment is being operated.

I have found the equipment of my invention highly practical in construction and operation and while I have described'my invention incertain preferred embodiments I realize that modifications may be made and I desire that it be understood that no limitations upon my inventionare intended other than may be imposed by the scope of the appended claims.

As an example of one ofthe variations or modifications of my invention I may refer to any means for constantly activating the several reeds so that they are maintained in a state of'vibration. Such constant rate of vibration is at an amplitude at which electrical contact is maintained by the reed contact. However, upon nonreceipt of a tone the reed resonant to such tone may be dropped in amplitude of vibration sufiicient to effect the release of the associated contact. Thus a slight infinitesimal time lag incidental to building up the vibration of the reed is eliminated in such an arrangement by having the reeds operate at'full amplitude of vibration which is interrupted by the displacement of a oneach 180 of the type wheel-operatively .con-

trolled by said selector system, and electric circuit means. for simultaneously applying said permutations and combinations of simultaneously applied coded signal impulsesto said ratchet con trolled step-by-step selectorsystem for ;controllingsaid printing device by-theconjoint'action of simultaneously applied impulses.

2. In a printing telegraph receiving system, means for receiving permutations and combinations of simultaneously applied multiple coded audio frequency signal impulses, electric circuit means for translating said simultaneously applied multiple audio frequency signal impulses into simultaneous direct current impulses and means including a type wheel wherein a complete alphabet appears on each 180 of the type wheel and operative through a range of approximately 180 for electrically translating said simultaneous direct current impulses into printed characters.

3. In a printing telegraph receiving system, means for receiving permutations and combinations of simultaneously applied multiple coded signal impulses, a multiplicity of pre-arranged electric matrix circuits, including individual cir- 1O cuit connections establishing a signal combination representative of a predetermined character, a multiplicity of relays controlled by said simultaneous applied multiple coded signal impulses for rendering said electric matrix circuits in: dividually and selectively effective, a printing control mechanism including a type wheel wherein a complete alphabet appears on each 180 of the type wheel, and a stepping relay associated with said printing control mechanism and operative through a range of approximately 180 under control of said simultaneously applied multiple coded signal impulses for selecting one of said electric matrix circuits and effecting thereby the printing of a selected character by said printing control mechanism.

4. A printing telegraph receiving system as set forth in claim 3 wherein the simultaneously applied multiple coded signal impulses are received at audio frequencies'and effect the establishment of circuits through the electric matrix circuits for the passage of direct current pulses to said printing control mechanism.

5. A printing telegraphreceiving system asset forth in claim 3 in which the simultaneously applied multiple coded signal impulses arefreceived at audio frequencies and effect resonant vibra-. tion of a multiplicity of reeds and which in .turn control direct current relay circuits for. selectively conditioning an individual electricmatrix circuit representative of the selected character said multiplicity of electric matrix circuits.

6. A printing telegraphreceiving systemras set forth in claim 2 in which said translating means include a multiplicity ofreeds individually .resonant to the individualfrequencies or said simultaneously applied multiple. coded signal impulses and direct current actuatedrelay circuits con trolled subsequent to the attainment of a predetermined amplitude by, said reeds.

7 A printing telegraphreceiving system as set forth in claim 1 including a tape feed mechanism for advancing a tape longitudinallyof the path of both ofthe alphabets onsaid type wheel and a striker bar selectively orientatable to a position aligned with either of said alphabets for presenting the tape toeitherrow of alphabets on said type wheel.

8. In a printing telegraph receiving system, means for receiving permutations and combinations of simultaneously applied multiple :coded signal impulses, .a selector switch controlled by said impulses, a printing device including a type wheel wherein a complete alphabet appears on each 180 of the type wheel, and means disposed within dimensional limits of approximately 180 and controlled bysaid selector switch -tor controlling said printing device said means also including a matrixof electrical circuits beyond the aforesaid dimensional limits containing prearranged circuits individual to the permutation and combination signal impulses representative of each of the characters being printed.

9. In a printing telegraph receiving system, means for receiving multiple permutations and combinations of simultaneously applied multiple coded signal impulses, a converter including a multiplicity of individually resonant reeds, responsive to the multiple coded signal impulses, individual relay contacts controlled by each of said reeds and operative to establish closed electrical circuits when said reeds are vibrated substantially at resonance, separate relays controlled by each of said relay contacts, an armature and actuator individual to each of said last mentioned relays, a multiplicity of contact arms controlled by each of said actuators, an electric matrix including contacts associated with each of said contact arms and connected in circuits corresponding in number to the number of electrical pulses being transmitted, a stepping relay having a multiplicity of radially disposed contact positions disposed within an angular range of approximately 180 corresponding in number to the number of electrical circuits through said electric matrix and electrically connected to the contacts thereof, a stepping relay arm operative over said radially disposed contacts within an angular range of approximately 180 and a printing device including a type wheel wherein a complete alphabet appears on each 180 of the type wheel and selectively controlled by said stepping relay arm and responsive to selected signal permutations and combinations established through said matrix.

10. In a printing telegraph receiving system, a receiving circuit responsive to a predetermined range of audio frequency permutations and combinations of signal impulses, a multiplicity of tuned reed relays individually responsive to audio frequency signal impulses within said predetermined range of audio frequency, said tuned reed relays each including a vibratory armature and a contact member spacially related thereto whereby selected electrical circuits are closed through said armatures and their associated contacts when the vibration of said armatures reaches a predetermined amplitude, direct current relays each having relay windings electrically connected with the aforesaid contacts and a source of direct current, an armature associated with each of said direct current relays, a movable actuator connected with each of said last mentioned armatures, a multiplicity of contact arms controlled by each of said movable actuators, said contact arms corresponding in number to the number of signal permutations and combinations incident upon said receiving circuit, contact elements associated with each of said contact arms, electrical circuit connections extending from the contact elements associated with the contact arms controlled by one of said actuators with the contact arms controlled by the adjacent actuator and forming an electrical matrix having circuit paths therethrough individual to each of the signal permutations and combinations incident upon said receiving circuit, a stepping relay including individual contacts connected to the aforesaid circuit connections, contact arms movable over said individual contacts, a printing telegraph device including a type wheel wherein a complete alphabet appears on each 180 of the type wheel, and means for selectively connecting said printing 12 telegraph device with said last mentioned contacts and effecting the printing or a character corresponding to the signal permutation and combination established by individual paths through said electrical matrix.

11. A printing telegraph receiver comprising a step-by-step selector having a multiplicity of contacts forming circuit terminals or permutation and combination direct current pulses corresponding to signals and arranged in a curved path extending through approximately 180, a pair of rocking arms selectively movable over said contacts, a type-wheel having a double alphabet printing face thereon, one alphabet oi which extends over 180 of the type wheel and the other alphabet of which extends over the other 180 of the type wheel, means for driving said type wheel in timed relation to the movement of said rocking arms, a tape movable adjacent the double alphabet printing face of said type wheel, and means for selectively moving said tape into-register with either alphabet on said double alphabet type wheel, said double alphabet type wheel being mounted within the curved path of said multiplicity of contacts.

12. A printing telegraph receiver comprising a step-by-step selector having a multiplicity of contacts forming circuit terminals for permutation and combination direct current pulses corresponding to signals and arranged in a curved path extending through approximately 180, a rocking arm movable unidirectionally step-bystep for selectively sweeping said contacts, a shaft extending from said arm, a ratchet mechanism connected with said shaft for imparting unidirectional step-by-step movement thereto, a type wheel connected with said shaft and carrying type designations constituting a complete alphabet appearing on each 180 of the periphery thereof, a tape movable tangentially to the designations on the periphery of said type wheel, and means for selectively moving a tape into register with the designations on the periphery of the type wheel.

JAMES D. DURKEE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,056,452 Hoover et al Oct. 6, 1936 2,058,398 Bear Oct. 27, 1936 2,096,954 Bellamy et a1 Oct. 26, 1937 2,173,154 Bernard Sept. 19, 1939 2,192,242 Robinson et a1 Mar. 5, 1940 2,262,766 Jansson Nov. 18, 1941 2,342,886 Murphy Feb. 29, 1944 2,406,835 Herbst Sept. 3, 1946 

